ASoC: max98373: check for device node before parsing

Below Oops is caused in a system which uses ACPI instead of device node:

of_get_named_gpiod_flags: can't parse 'maxim,reset-gpio' property of node '(null)[0]'
BUG: kernel NULL pointer dereference, address: 0000000000000010

This patch avoids NULL pointer deferencing by adding a check before parsing
and initializes to make reset-gpio pin as invalid.

Signed-off-by: Sathyanarayana Nujella <sathyanarayana.nujella@intel.com>
Signed-off-by: Jairaj Arava <jairaj.arava@intel.com>
Link: https://lore.kernel.org/r/1569702150-11976-1-git-send-email-sathyanarayana.nujella@intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/sound/soc/codecs/max98373.c b/sound/soc/codecs/max98373.c
index e609abc..eb709d5 100644 (file)
--- a/sound/soc/codecs/max98373.c
+++ b/sound/soc/codecs/max98373.c
@@ -901,16 +901,20 @@ static void max98373_slot_config(struct i2c_client *i2c,
                max98373->i_slot = value & 0xF;
        else
                max98373->i_slot = 1;
-
-       max98373->reset_gpio = of_get_named_gpio(dev->of_node,
+       if (dev->of_node) {
+               max98373->reset_gpio = of_get_named_gpio(dev->of_node,
                                                "maxim,reset-gpio", 0);
-       if (!gpio_is_valid(max98373->reset_gpio)) {
-               dev_err(dev, "Looking up %s property in node %s failed %d\n",
-                       "maxim,reset-gpio", dev->of_node->full_name,
-                       max98373->reset_gpio);
+               if (!gpio_is_valid(max98373->reset_gpio)) {
+                       dev_err(dev, "Looking up %s property in node %s failed %d\n",
+                               "maxim,reset-gpio", dev->of_node->full_name,
+                               max98373->reset_gpio);
+               } else {
+                       dev_dbg(dev, "maxim,reset-gpio=%d",
+                               max98373->reset_gpio);
+               }
        } else {
-               dev_dbg(dev, "maxim,reset-gpio=%d",
-                       max98373->reset_gpio);
+               /* this makes reset_gpio as invalid */
+               max98373->reset_gpio = -1;
        }
 
        if (!device_property_read_u32(dev, "maxim,spkfb-slot-no", &value))